Breathing assist apparatus

ABSTRACT

A device for providing assistance to persons with emphysema and problems relating to breathing. Essentially the invention provides means for applying pressure to the abdominal and lower rib region which assists in forcing air from a person&#39;&#39;s lung. The pressure is applied during the exhalation phase of the breathing cycle and the pressure applying means is activated by the person&#39;&#39;s efforts to exhale. The pressure is released upon completion of the exhalation phase avoiding interference with the inhalation phase.

United States Patent [151 3,683,655 White et a]. [451 Aug. 15, 1972BREATHING ASSIST APPARATUS 3,566,862 3/ 1971 Schuh et al. 128/302 [72]Inventors: Arlton H. White, 6947 Meadowcreek Dr., Dallas, Tex. 75240;John TaPP Chapman, 3606 Lovers Lane, Attorney-Samuel M. Mims, Jr. D

alla, Tex 75225 ABSTRACT [22] Filed: March 27, 1970 A device forproviding assistance to persons with PP 23,197 emphysema and problemsrelating to breathing. Essentially the invention provides means forapplying pres- [52] Us Cl 128/302 sure to the abdominal and lower ribregion which .Cl e e e e e e e e e e e e e assists in forcing air from aperson's lung. The pres [58] Fie'ld 28/28 30 2 sure is applied duringthe exhalation phase of the breathing cycle and the pressure applyingmeans is activated by the person's efforts to exhale. The pressure [56]References Cited is released upon completion of the exhalation phaseUNITED STATES PATENTS avoiding interference with the inhalation phase.402,779 5/1889 Steinhoff 128/302 7 Clains, 5 Drawing Figures AMPLIFIER8r MOTOR CONTROL PRESSURE ADJUSTMENT DEVICE PATENTEllAuslslsrz 3.683.655

SHEEI 1 [IF 3 AMPLIFIER aMoToR CONTROL PRESSURE ADJUSTMENT [6 DEVICE ,7PRESSURE SUPPLY MECHANISM Fig. A/PL TON H. WH/TE 7 JOHN S. CHA P/I/IA/VPATENTEDAUSISIBTZ 3,683,655

SHEET 2 [1F 3 I TO DRIVE l I MECHANISM /.0/.5 SECONDS .PRESSURE(TYPICAL) (PSIG) Fig, 5 (SECONDS) PATENTEU ms 1 5 m2 SHEET 3 [IF 3 1BREATHING ASSIST APPARATUS Emphysema is a disease affecting a personslungs and the muscles used in exhaling air from the lungs. During theinhalation phase of breathing, the normal lung capability of personssuffering from emphysema seems to be a relatively little affected andbreathing is almost normal. In a normal person, air is exhaled byelastic recoil without muscular effort whereas the act of expiration inpersons with emphysema is accomplished by active muscular work.Furthermore, with emphysema, there is atrophy of the diaphragm whichbecomes markedly depressed so'that it no longer serves as a functionalrespiratory muscle. Thus, a characteristic of emphysema is difficulty inexhalation or expiration. The principle upon which this invention isbased is that of providing compression of the abdomen and lower ribsduring the exhalation phase of breathing and initiating the compressioncoincident, as closely as possible, with the beginning of exhalation, inreplacement of the elastic recoil or of active muscular exhalation. Asan added benefit, in applying a pressure to the diaphragm and pushing itupward, there is the probability of returning the muscle to a partialfunctional state.

Accordingly, it is an object of this invention to pro vide assistanceduring the portion of the breathing cycle when assistance is requiredand, thereafter, to release the assisting means so as not to interferewith otherwise normal breathing.

Another object of this invention is to provide sensi tive means fordetecting effort to exhale and, upon detection, activating the breathingassist means.

Still another object is to detect efforts to exhale without impeding orhindering the exhalation of air from a persons lungs.

A still further object of this invention is to provide breathingassistance which is foolproof in operation and does not expose the userto hazards or danger especially while sleeping or in a semiconsciouscondition.

Another object is'to apply pressure over the time period of theexhalation phase of breathing which pressure increases to a maximum andthen decreases corresponding to the normal movement of a personsdiaphragm.

Another object of this invention is to provide a structure which iscompact for ease of location, use and storage and, as well, simple inconstruction and with relatively few moving parts for long life andmaintenance free operation.

Other objects and advantages reside in the details of construction andoperation as more fully described and claimed hereinafter and as shownin the accompanying drawings.

The drawings are as follows:

FIG. 1 is a representation of the preferred embodiment of the breathingassist apparatus.

FIG. 2 is a block diagram of the breath signal amplifier and controlcircuit for activating the pressure supply apparatus of FIG. 4.

FIG. 3 is a detailed circuit diagram of the block diagram of FIG. 2.

FIG. 4 shows a side elevation view of a mechanism and air supplyreservoir for applying pressure to the abdomen and lower rib region.

FIG. 5 is a curve of the pressure provided by the mechanism and airsupply reservoir of FIG. 4 over the time period of the exhalation phaseof breathing.

Describing now the breathing assist apparatus, FIG. 1 shows inrepresentative form a preferred embodiment of the apparatus. In thisembodiment, the means for applying pressure to the abdomen and lower ribregion is by an expandible sack 11 which can be strapped in place bymeans of a belt 10. The belt extends lengthwise of the sack 11 and ismaintained in place by loops, tabs or a separate cloth cover enclosingthe sack. Sack 11 is elongated, double walled, expandible, sealed ateither end and leakproof. Suitable construction materials for the sackare rubber and plastics. Two openings are provided in sack 11, one ofwhich connects with tube 16 and the other with air supply hose 20. Ateither end of belt 10 are clasps 12 and 13 suitable for joining togetherand holding belt 10 and sack 11 in place. The exact construction of theclasps l2 and 13 is not material to this invention and could be replacedby, for example, a buckle arrangement. However, it is preferred that theclasp arrangement allow the wearer to adjust the belt 10 to the mostefiective position and degree of tightness and permit easy and quickrelease in the manner of standard safety, or seat, belts.

The tube 16 communicates with a hand operated bulb pump 15 controlled byscrew closure 17. The purpose of the hand operated bulb pump is toinflate sack 1 I initially and, thereafter, to adjust the pressureinside the sack and, also, bellows 71 (described as part of FIG. 4hereinafter). With screw 17 closed, squeezing bulb pump 15 increases theair supply in the sack and thus the pressure. When screw 17 is loosened,air escapes and the pressure within the sack is reduced.

With belt 10 in position, the wearer next positions on his head theheadset support 25 to which is attached strap 26 supporting microphone27. Headset 25 may be of any convenient construction and, instead offitting over the head and down by the side of the persons ears as shown,may consist of a strap encircling the head. In any event, the purpose ofthe headset is to provide support for microphone 27 so that it may bepositioned in front of the wearers mouth and nose. Microphone 27 is ofthepiezoelectric crystal type and, when the wearer begins to exhale, nomatter how slight, the breath impinges directly on the microphone andcauses an electrical signal to be produced. The electrical signal is fedby leads 28 to the amplifier and motor control 30.

It can be seen that, if microphone 27 is positioned in front of thewearers mouth and nose, there is no impediment to breathing such asmight be occasioned by a mask or sensor operating on a pressure dropprinciple at the beginning of the exhalation cycle. This is not to saythat a mask fitting over the wearers nose and mouth might not berequired at times, for example, in a hospital in conjunction with otherequipment and medication for the wearer. If a pressure drop principle isemployed, the change in pressure may be used to close a switch andgenerate the electrical signal to the amplifier and motor control. Inaddition, other kinds of sensors than microphone 27 may be used such ashot wire anemometers and thermistors which produce electrical signals bychanging resistance to current flow as the exhaled air passes thesensor. Whatever device is used, however, the requirement is for highsensitivity to small movements of air and rapid response so as toinitiate timely activation of the pressure supply mechanism.

The amplifier and motor control is shown in block diagram in FIG. 2 andin detail circuit diagram in FIG. 3. Describing the block diagram ofFIG. 2, AC power is fed into the control by line 31 whose plug end maybe connected into any suitable source of 1 -120 volt AC power such as isstandard in homes, offices and hospitals. Within the control, powersupply 32 generates a B-lvoltage and this voltage is supplied throughlead 33 to leads 35 and 36. Lead 35 is connected to amplifier 37 andlead 36 to the relay trigger circuit 39. The signal from microphone 27is fed through lead 28 to amplifier 37. The amplifier 37 amplifies thesignal and feeds the signal through lead 38 to the relay trigger circuit39. The coincidence of a signal from amplifier 37 and the B+ voltagesupplied through line 36 permits a silicon controlled rectifier in thetrigger circuit to turn on and provide an output to activate powercontrol relay 40 and move its armature. Movement of the armature ofrelay 40 moves switch contact 55 to the position shown in dashed linesand the AC power from line 31 then feeds directly through leads 54 and56, leaf spring 49 of switch 45, and lead 46 to a motor in the pressuresupply mechanism. Lead 47 is the return line from the motor. Thepressure supply mechanism will be described subsequently in connectionwith FIG. 4. However, for clarity of description at this point, itshould be noted that a cam is carried on the motor and has a contactsurface such that switch contacts 49 and 50 of switch 45 remain in theirclosed position until the motor is energized. As the motor begins toturn, the cam surface and a cam follower then cause the switch contacts49 and 50 to move to the position as shown in dashed lines and,thereupon, to connect the motor directly to the source of AC power byway of switch contact 49. The momentary lapse of power to the motor inswitching from one line to another has been found not to interfere withits continued operation. Movement of switch contact 50 to the positionshown in dashed lines interrupts the B+ voltage supply to relay triggercircuit 39 through reset line 57 and the armature of power control relay40 and switch contact 55 return to their normal position. As the motorand cam rotate through a complete revolution, the cam surface andfollower permit switch contacts 49 and 50 to return to their normalposition and the AC power to the motor is disconnected. A back EMF fordynamic braking of the motor is provided by a circuit which includespower supply 32, line 51, switch contact 55, lead 56, switch contact 49in its normally closed position, and lead 46 to the motor. In thisstate, the control is in condition to receive the next signal frommicrophone 27 and repeat the sequence of steps described above.

FIG. 3 shows the block diagram of FIG. 2 in detailed circuit form. InFIG. 3, the corresponding portions of the circuit diagram have beenoutlined with dashed lines to indicate the portion of the circuitproviding the various functions described above such as the powersupply, amplifier, relay trigger circuit, etc. The silicon controlledrectifier mentioned in the description of FIG. 2 is shown as at 52.Similarly, the dynamic braking voltage is supplied by means of thetransformer and diode combination shown generally as at 53 and thevoltage is fed to the motor by means of lead 51 through the normallyclosed leaf switch 55, lead 56, switch contact 49 and lead 46. Since theoperation of the circuit of FIG. 3 has been described in general termsin connection with FIG. 2 and the circuit operates in a straight forwardfashion to provide the control desired in accordance with thisinvention, it is not deemed necessary to describe in detail here all thecircuit elements of the circuit diagram. It should be understood thatother circuits can be provided that will provide the equivalent functionto that of FIG. 3.

Turning now to the pressure supply mechanism 19, FIG. 4 shows in a sideelevation view the mechanism for providing an air pressure supply tosack 11. The motor and cam discussed above in connection with FIG. 2 isshown in FIG. 4 as 60 and 61 respectively. The centerline of cam 61 ismounted on the output rotor of motor 60. Motor 60 may be a variablespeed or a constant speed motor with the .proviso that, either by a slowmotor speed or by suitable reduction gearing, the output rotor rotatesdesirably at approximately 30 revolutions per minute which is adequateto provide assistance for a breathing rate of 20 complete cycles perminute. It is understood, of course, that motor 60 may be set to thespeed which corresponds to the desired breathing rate.

Switch 45, described above, is shown mounted on the base of motor 60 sothat cam follower 62 may control the movement of switch contacts 49 and50 according to the surface provided for cam 61. The action of the cam,cam follower, leaf springs and control of power has been describedabovewith respect to the operation of the control of FIG. 2.

Arm 63 is movably mounted by bolt 64 located eccentrically on cam 61.Arm 63 terminates in clevis 65 which is connected to one end of rod 66.Rod 66 extends through two linear bushings 67 and 68 and is connected atits other end to connector plate 69. Connector plate 69 is attached atthe center of a circular plate 70. A bellows 71 is in position betweencircular plate and a like circular plate 72. In turn, circular plate 72is connected to an end support member 73. The base of motor 60, bearings67 and 68, and the end support plate 73 are all supported from a basemember 74. An opening 75 is shown in dashed lines through circular plate72 and the support member 73 and communicates with pipe 76. The end ofhose 20 (see FIG. 1) is then fitted over the end of pipe 76.

In operation, as the motor rotates, arm 63 is moved in an oscillatingback and forth motion by its eccentric mounting to cam 61. Theoscillating back and forth motion of arm 63 is translated by clevis 65to a straight back and forth motion of rod 66. As rod 66 moves back andforth, bellows 71 is compressed from or permitted to return to itsnormal position, as the case may be, and the air contained withinbellows 71 is transmitted through hose 20 to sack 11 and back to bellows71.

The mechanism of FIG. 4 for compressing bellows 71 is only one of themany possible such mechanisms. For example, bellows 71 may be rotatedand moved up and down by the force of a rod pressing near its midpointon plate 69 with the rod being pivoted at one end and moved at its otherend by a crank and slider rotated by motor 60. As another means, motor60 and cam 61 may be mounted to bear against plate 69 with bellows 71being compressed and released as a function of the surface of cam. It iseven possible for motor 60 and cam 61 to be positioned internally ofbellows 71 with push and pull being exerted by arm 63 suitably attachedto plate 69. Still another means for moving bellows 71 is by a motorwith a centrally rotated helical screw which is advanced or retracted bythe direction of rotation of the motor. The advance of the screw bearingagainst plate 69 compresses the bellows and retraction of the screwpermits the bellows to assume its normal position. In all theseembodiments, suitable modifications would be made to carry out therequired electrical connection to and operation of the motor controlcircuit and switches. Furthermore, although perhaps not as feasible forthe purposes of this invention as a source of air pressure, bellows 71and its associated mechanisms could be replaced by an air compressor anda valve arrangement controlled by the signal from microphone 27. It isalso conceivable that the pressure to the abdomen and lower ribs couldbe applied by a plate movable by electromotive force or other mechanism.

As previously indicated, the motor rotor is set to rotate atapproximately 30 revolutions per minutebecause the breathing cycle forinhalation and exhalation for persons with emphysema may be faster thannormal and as short a time period as 3 seconds. FIG. 5 shows a curve ofpressure against time for the pressure created by the pressure supplymechanism. According to the curve, pressure builds up gradually fromzero to a maximum, dwells momentarily and then diminishes gain to zero.The maximum pressure coincides in the exhalation phase with the need forgreatest movement of the persons diaphragm. Actually, during part of themotor rotation .cycle, a negative pressure is created which assists inpulling air from sack 11.

Described briefly in its entirety, the person with a lung problempositions the sack around his abdomen and lower ribs and places themicrophone support mechanism around his head so that the microphone isadjacent his mouth and nostrils. Upon exhalation, the microphone sensesimpingement of the wearers breath at the beginning of exhalation andsends a signal to the control mechanism. The signal is amplified andused to trigger selective operation of switches which permit current toflow to and rotate an electric motor. A suitable mechanism translatesthe rotation of the motor to cause compression of a flexible air supplyreservoir. Upon compression, air is transferred to the sack and beltaround the wearer. The sack inflates and causes pressure against theabdomen and lower rib portion and, by compression thereof, assists thewearer in exhaling air from his lungs. The rotation time of the motor isapproximately 2 seconds and during and at the end of each rotation cyclethe switches are reset and the control mechanism is conditioned for thenext signal from the microphone.

In experiments with victims of emphysema a marked degree of improvementin arterial oxygen, that is, reduction in arterial carbon dioxide, isfound on use of the breathing assist apparatus of this invention. Inmeasurements made with an intraesophageal balloon in patients wearingthe breathing assistor, the results indicate sufficient pressureincreases within the chest to assist in expelling respired gas. Threepatients were tested two normal subjects and one with emphysema. Theaverage increase in end-expiratory intrathoraclc pressure produced bythe device was approximately 5 cm. H 0. Measurements were then made ofthe change in gaseous content of arterial blood produced by applicationof the breathing assistor to two emphysema patients. These measurementsindicated a reduction in partial pressure of CO and an increase inpartial pressure of 0 Also one of these patients showed a change inarterial blood pH from 7.32 to 7.45 after only 10 minutes of use of thebreathing assistor. All of these responses indicate a significant changetoward more normal values. No impediments to breathing were noticeableby the wearers and no health hazard, safety hazard or undue pressure wasnoted in any of the tests conducted over extensive periods therebyindicating suitability of the apparatus for the purpose intended.

A preferred embodiment of the apparatus has been described above. Itshould be noted that many variations and deviations in equipment arepossible without departing from the scope of the invention. For example,various kinds of transducers have been mentioned above for use in placeof microphone 27. As other examples, a variety of materials,arrangements and 'mechanisms have been mentioned as suitable forproviding the pressure upon a persons abdomen and lower ribs. Thus, theinvention hereof is suitable for being accomplished by a number of meansand embodiments without departing from the scope of the invention asdefined in the claims below.

What is claimed is: I

1. Apparatus for assistance in breathing which comprises aself-contained fluid and actuating means for applying pressure to theabdomen and lower ribs over a time period equivalent to the exhalationphase in breathing, said means assisting in forcing air from a personslungs and releasable at the end of the exhalation cycle, and sensingmeans minimizing impediments to breathing and operable upon detection ofbreath upon exhalation for actuating said means for applying pressure.

2. Apparatus for assistance in breathing which comprises a belt forattachment around the abdominal and lower rib region, said beltincluding expandable means, a reservoir connected to said expandablemeans and providing a self contained fluid supply, actuating means, andsensing means detecting the impingement of breath, said sensing meansproviding an output upon the beginning of exhalation to said actuationmeans whereby said actuating means is activated and causes fluid to flowfrom said reservoir to said expandable means during exhalation and toreturn to said reservoir at the end thereof.

3. The apparatus as defined in claim 2 which said sensing meanscomprises a microphone supported in non-breathing impediment manneradjacent a persons nose and mouth.

4. The apparatus as defined in claim 2 in which said expandable meanscomprises an elongated sack and said reservoir is compressible by saidactuation means.

5. ln a breathing assist apparatus, a pressure applying means forpositioning around the abdomen and lower ribs, a reservoir of airconnected to said pressure applying means in a self contained system,actuation means for alternately transferring air in said system to andapplying pressure to the abdomen and lower ribs over a time periodequivalent to the exhalation phase in breathing, said means assisting inforcing air from a persons lungs and releasable at the end of theexhalation cycle, said means for applying pressure being actuatedperiodically corresponding to the breathing cycle of inhalation andexhalation.

1. Apparatus for assistance in breathing which comprises a selfcontainedfluid and actuating means for applying pressure to the abdomen and lowerribs over a time period equivalent to the exhalation phase in breathing,said means assisting in forcing air from a person''s lungs andreleasable at the end of the exhalation cycle, and sensing meansminimizing impediments to breathing and operable upon detection ofbreath upon exhalation for actUating said means for applying pressure.2. Apparatus for assistance in breathing which comprises a belt forattachment around the abdominal and lower rib region, said beltincluding expandable means, a reservoir connected to said expandablemeans and providing a self contained fluid supply, actuating means, andsensing means detecting the impingement of breath, said sensing meansproviding an output upon the beginning of exhalation to said actuationmeans whereby said actuating means is activated and causes fluid to flowfrom said reservoir to said expandable means during exhalation and toreturn to said reservoir at the end thereof.
 3. The apparatus as definedin claim 2 which said sensing means comprises a microphone supported innon-breathing impediment manner adjacent a person''s nose and mouth. 4.The apparatus as defined in claim 2 in which said expandable meanscomprises an elongated sack and said reservoir is compressible by saidactuation means.
 5. In a breathing assist apparatus, a pressure applyingmeans for positioning around the abdomen and lower ribs, a reservoir ofair connected to said pressure applying means in a self containedsystem, actuation means for alternately transferring air in said systemto and from said reservoir and said pressure applying means, and breathsignal detection means controlling said actuation means.
 6. In abreathing assist apparatus as defined in claim 5, hand operated pumpmeans for adjusting the pressure in said pressure applying means and insaid reservoir.
 7. Apparatus for assisting in breathing which comprisesa self-contained fluid and actuating means for applying pressure to theabdomen and lower ribs over a time period equivalent to the exhalationphase in breathing, said means assisting in forcing air from a person''slungs and releasable at the end of the exhalation cycle, said means forapplying pressure being actuated periodically corresponding to thebreathing cycle of inhalation and exhalation.